Fusible plug



B. P. TERRELL.

FUSIBLE PLUG. APPLICATION FILED OCT. 28, I9I9.

Patented May 3, 1921.

3 vwemtoc Witness Sigma go UNITED STATES PATENT OFFICE.

FUSIBLE PLUG.

Application filed October 28, 1919.

To all whom it may concern:

Be it known that I, BENJAMIN P. TER- nnLL, a citizen of the United States, residing at Varrenton, in the county of Warren and State of North Carolina. have invented, a new and useful Fusible Plug, of which the following is a specification.

This invention relates to new and useful improvements in steam boilers and more particularly to low water alarms employed in connection therewith.

The primary object of the invention is to provide a device of this character which will permit the engine to proceed in the event that the fusible plugs employed in connection with the boiler are caused to fuse, due to the collection of foreign matter thereon, which foreign matter often causes such fusing to take place, when the boiler has a sufficient quantity of water therein for the efficient operation of the engine.

A further object of the invention is to provide means for directing the steam and water exhausting from the boiler when the plugs are fused, to a point exteriorly of the fire box and in full viewv of the engineer, or at a point to eliminate all possibility of the operators of the engine being scalded or otherwise injured by the exhausting hot water or steam.

A further object of the invention is to provide means disposed within a boiler for indicating before the water within the boiler has reached a dangerously low level, which low level of water would impair the life of the crown sheet forming a part of the boiler.

A further object of the invention is to provide a device of this character including a removable head supporting a plurality of fusible plugs the same being capable of application to a boiler from a point within the fire box of a locomotive thereby eliminating the necessity of entering the boiler for positioning the same.

A further object of the invention is to provide a head of this character which may be applied to the ordinary boiler construction now in use, without the necessity of changing or construction thereof.

With the foregoing and other objects in view which will appear as the description proceeds, the invention resides in the combination and arrangement of parts and in the details of constructionhereinafter described and claimed, it being understood altering the Specification of Letters Patent.

Patented May 3, 1921.

Serial No. 333,999.

that changes in the precise embodiment of the invention herein disclosed, may-be made within the scope of what is claimed, without departing from the spirit of the invention.

Referring to the drawing Figure 1 illustrates a diagrammatic view disclosing the application of the invention, to a boiler.

' Fig. 2 illustrates a sectional view through the device showing the interior construction thereof.

Referring to the drawing in detail, the device forming the subject matter of the being shown as disposed directly under the crown sheet, in the usual manner. I

The upper wall 8 of the boiler, is spaced from the crown sheet 6, to contain water therebetween, which water is employed for generating the steam for running the locomotive engine. In the usual construction of boilers, the crown sheets are provided with screw threaded openings, indicated at 9, which openings ordinarily accommodate a fusible plug, which, when the water within the boiler reaches a low level, melts, thus indicating that the water in the boiler is dangerously low.

The invention includes a boiler having a crown sheet 6, and an upper wall 8, there being provided a suitable threaded opening in the crown sheet in which is positioned the head 5', which is formed with a hollow portion 6, that is provided with a central partition 7 dividing the hollow portion 6 into adjacent compartments 8' and 9, the compartment 9 having communication with the atmosphere through the pipe 10, extending through the upper wall of the boiler, one wall of the compartment 9' being provided with spaced openings 11' which accommodate the fusible plugs 12', and as shown, these plugs are disposed in spaced relation with each other, so that the same will control different levels within the boiler.

The compartment 8' has communication with the atmosphere through the pipe 13, which also extends through the boiler.

The hollow portion 6, is also provided with an opening 14, disposed adjacent the lower edge thereof, on a line with the upper surface of the crown sheet, in which the head is positioned, so that the fusible plug 15, supportedtherein, will fuse, when the Water In this construction, it is to be noted that when one signal has been sounded, indicat ing that the water in the boiler is reaching a low level, the valve member 16 is then operated to shut off communication between the compartment 9 and atmosphere, thus permitting the engineer to replenish water and proceed to terminal, if however, the water reaches the danger point, or a point which would permit the crown sheet to be burntout, a signal is operated by the steam through pipe 13, as before described.

It might be further stated that the fusible plugs are often fused, due tothe collection of foreign matter thereon, which foreign matter covers one of the inner faces of the plugs, and prevents the same from contacting- V may now be generated for the operation of the engine. 7

It is believed that in view of the foregoing description a detail description of the operation of the device, step by step, is unnecessary for a clearunderstanding of the invention.

What is claimed is In a boiler with a crown sheet having a threaded opening therein, a hollow plug positioned within the opening, a partition in the plug and dividing the same into compartments, fusible plugs positioned in the walls of one compartment, and a fusible plug positioned in the wall of theopposedcompartment, the fusible plug of the latter coinpartment being in closer relation with the crown sheet than the plugs of the opposite compartment, and means in communication with the respective compartments for pro viding communication between the compartments and the atmosphere.

In testimony that I claim the foregoing as my own, I have hereto affixed my signa ture in the presence of two witnesses.

BENJAMIN TERRELL.

Witnesses A. C. BLALOCK, W. S. PRICE. 

